THE GIST

- Musicians might want to get outside more or take vitamin D supplements.

- People who live in dark, northern places can't get enough vitamin D from sun exposure.

During his short life, Austrian composer Wolfgang Amadeus Mozart suffered from many of the era's common illnesses, including smallpox, typhoid fever, tonsillitis and upper respiratory tract infections.

What exactly it was that killed him in December 1791 at age 35, however, is still a matter of debate -- with theories ranging from poisoning to renal disease.

Now, two researchers offer a new theory: vitamin D deficiency. In his high-latitude home in Austria, Mozart was probably running low on the sunshine vitamin for half the year. That deficiency may have put the musician at risk for many of the illnesses he suffered from.

HSW: Everything You Need to Know About Vitamin D

If only Mozart had known about vitamin D and had access to supplements, he could have doubled his lifetime's output of work, mused William Grant, a retired NASA atmospheric physicist who has been following vitamin D research with great interest for the past decade. And, he argued, the same goes for several other famous musicians who died at young ages.

While some researchers remain skeptical, Grant thinks Mozart's story holds a cautionary tale for modern musicians, who might want to consider getting outside for a practice session or two.

"Almost every disease has a vitamin D connection these days," said Grant, who is not a doctor, but is affiliated with the Sunlight, Nutrition and Health Research Center, a pro-vitamin D research and education association. "I think modern-day musicians are unaware of the fact that by staying indoors, they are not getting the adequate amount of vitamin D that they need."

Mozart's death has long been shrouded in mystery. The musician was buried three days after he died, said William Dawson, a retired orthopedic surgeon, and past president of the Performing Arts Medicine Association. And an autopsy was never performed on his body.

Testimonies and reports about the composer's death were not reviewed until 30 years later. Even then, the documents were full of conflicting details. To complicate the situation even more, medical knowledge at the time -- more than two centuries ago -- was far behind what doctors know today. And since Mozart's time, the definitions of many medical terms have changed.

"They didn't know about vitamins," Dawson said. "They didn't know about bacteria. They didn't know about blood pressure. Mozart's physicians were as high quality as he could get. They just didn't have the knowledge or technology to treat him."

Dawson reviewed 81 references in the literature that addressed the question of what actually happened to Mozart at the end of his life. In a paper published last year in the journal Medical Problems of Performing Artists, he chronicled and organized those theories.

Many of the papers he looked at sited chronic kidney disease as the cause of lots of Mozart's problems, including his many secondary infections, like strep throat and pink eye. Those explanations are convincing enough, Dawson said, though he has his own pet theory for what ultimately killed the composer.

"They bled Mozart a lot as one of the treatments for his disease," he said. "I think they bled him too much and he died of acute blood loss."

Grant has a different point of view. He read Dawson's paper with a close eye on the time of year that Mozart tended to get sick. From 1762 to 1783, he wrote in a letter that was just published in the journal Medical Problems of Performing Artists, most of Mozart's infections occurred between mid-October and mid-May.

That's the time of year when people in places as far north as Austria simply can't make enough vitamin D from sun exposure. Plenty of studies in recent years have linked adequate vitamin D levels with lower risks for influenza, pneumonia, cardiovascular disease, cancers, autoimmune diseases and more.

The current recommended daily intake of vitamin D is 600 IU for most people, but some experts now advocate taking as much as 4,000 IU, which is currently the recommended upper limit for the vitamin (something no one should do without talking to their doctor first).

There's no way to prove or disprove Grant's theory, Dawson said, but he urged some caution.

"I am tempted to say that this is an idea that has its adherents, and it's out there in the literature," Dawson said. "Whether people choose to believe it is up to the individual reader."